Heat pipe assembly with bonded fins on the baseplate hybrid

ABSTRACT

A hybrid heat pipe assembly includes a baseplate dimensioned to be placed in surface contact with a device. The baseplate is configured to extract heat from the device. A plurality of fins is bonded to the baseplate. The fins are configured to transfer a first portion of the extracted heat from the baseplate to air surrounding the fins. A complex heat pipe extends from the baseplate and has an end positioned within the baseplate. The complex heat pipe is configured to receive and transfer a second portion of the extracted heat transferred from the baseplate. The complex heat pipe is configured to transfer the second portion of heat to a heat pipe fin stack to which.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/061,311, filed Oct. 8, 2014, which is fully incorporated herein byreference.

FIELD OF THE INVENTION

The following disclosure is directed generally to hybrid heat pipeassemblies.

BACKGROUND OF THE INVENTION

A device usually generates heat as a result of losses in efficiency. Aheat sink is a passive heat exchanger that can cool a device bytransferring heat generated by the device into a surrounding coolingmedium, such as air. A heat sink may have a baseplate that can extractheat from a device that is in contact with the baseplate. A heat sinkmay also include an assembly of fins bonded to the baseplate that cantransfer the extracted heat from the baseplate to the surroundingcooling medium. Thus, there is a flow of heat from the device throughthe baseplate and the fins to the surrounding cooling medium, therebyserving to cool the device in contact with the baseplate.

Since the heat sink is a passive heat transfer mechanism, there may besituations in which the heat sink is not able to adequately cool adevice in contact therewith. In such cases, a heat pipe apparatus mightbe applied. A heat pipe apparatus is also a heat exchanger than can coola device by transferring heat generated by the device into a surroundingcooling medium. The heat pipe apparatus may include an evaporator platethat can extract heat from a device that is in contact with theevaporator plate. The apparatus may also include a plurality of heatpipes in contact with the evaporator plate that can transfer heat fromthe evaporator plate to another location using liquid-to-vapor phasechanges.

Each of the heat pipes includes a working fluid, such as water, sealedin a long thin walled cavity under vacuum. The cavity may be cylindricalor rectangular, but is not limited thereto. When heat is applied to aportion of the heat pipe, the working fluid boils and is converted intovapor. The vapor moves from the heated portion, or an evaporating area,of the pipe to a lower temperature area, or a condensing area, of theheat pipe via an adiabatic portion of the pipe where no phase changetakes place. The lower temperature area of the heat pipe is at anopposite end of the heat pipe from the end of the heat pipe in contactwith the evaporator plate. In the lower temperature area of the heatpipe, the vapor will condense back into a liquid. The liquid will moveback to the heated area of the heat pipe via the adiabatic portion ofthe pipe to be heated and evaporated again. Thus, a two-phase flow cycleis created.

The condensed liquid moves from the lower temperature area of the heatpipe to the heated area of the heat pipe using gravity or a wickingstructure. If the liquid moves back to the heated area as a result ofgravity, the heat pipe has been oriented in such a way that gravity candraw the condensed liquid down toward the heated portion of the heatpipe. For example, such an orientation may include a heat pipe beingangled downwardly from the lower temperature area of the heat pipe tothe heated area of the heated pipe. This allows gravity to draw thecondensed liquid from the higher, condensing area of the heat pipetoward the lower, evaporating area of the heat pipe.

A large fin stack is positioned around the lower temperature area, andpossibly the adiabatic portion, of the heat pipe. The fin stack cantransfer the heat away from the heat pipes into the air through forcedor natural convection.

However, even such a heat pipe apparatus may not be effective todissipate heat from certain devices that are either exceedinglyinefficient or of a size significant enough to require a greater coolingcapacity than such a heat pipe apparatus can provide on its own.

SUMMARY OF THE INVENTION

Described herein are multiple example embodiments related to hybrid heatpipe assemblies.

In an aspect, a hybrid heat pipe is provided. The assembly includes abaseplate dimensioned to be placed in surface contact with a device, thebaseplate being configured to extract heat from the device. The assemblyadditionally includes a plurality of fins bonded to the baseplate, thefins being configured to transfer a first portion of the extracted heatfrom the baseplate to air surrounding the fins. The assembly furtherincludes a complex heat pipe extending from the baseplate and having anend positioned within the baseplate, the complex heat pipe beingconfigured to receive and transfer a second portion of the extractedheat transferred from the baseplate. Moreover, the assembly includes aheat pipe fin stack to which the complex heat pipe is configured totransfer the second portion of heat, the heat pipe fin stack beingjoined to the complex heat pipe and configured to transfer the secondportion of the extracted heat received from the complex heat pipe to airsurrounding the stack.

In an example of the aspect, the complex heat pipe extends from thebaseplate and through the fins and the heat pipe fin stack. In anotherexample of the aspect, the fins are bonded to the baseplate in aplurality of groups. The groups are separated from each other by thecomplex heat pipe. In a further example of the aspect, the complex heatpipe extends from the baseplate and through two of the fin groups andthe heat pipe fin stack. In an additional example of the aspect, each ofthe complex heat pipes extends through the heat pipe fin stack.

In a further example of the aspect, the heat pipe fin stack includes aheat pipe protective fin into which the complex heat pipe extends. Theheat pipe protective fin is positioned on an opposite side of the heatpipe fin stack from the fins. In an example of the aspect, the heat pipeprotective fin is positioned adjacent to one end of the complex heatpipe. In yet another example of the aspect, another end of the complexheat pipe is embedded in the baseplate.

In an additional example of the aspect, the fins are mounted to anopposite side of the baseplate from a side of the baseplate in contactwith the device. In still another example of the aspect, the complexheat pipe is embedded in the baseplate. In a further example of theaspect, the complex heat pipe extends at an angle from the baseplate toan end of the complex heat pipe.

In a second aspect, a hybrid heat pipe assembly for cooling a device incontact is provided. The assembly includes a baseplate dimensioned to beplaced in surface contact with a device, the baseplate being configuredto extract heat from the device. The assembly also includes a pluralityof fins bonded to the baseplate, the fins being configured to transfer afirst portion of the extracted heat from the baseplate to airsurrounding the fins. The assembly further includes a complex heat pipeapparatus positioned within the baseplate, the apparatus including achamber positioned within the baseplate and a plurality of complex heatpipes secured within the chamber, the complex heat pipes extending fromthe baseplate and having ends positioned within the baseplate, thechamber being configured to receive a second portion of the extractedheat transferred from the baseplate and transfer the second heat portionto the complex heat pipes, the complex heat pipes being configured toreceive and transfer the second heat portion from the chamber. Theassembly additionally includes a heat pipe fin stack to which thecomplex heat pipes are configured to transfer the second portion ofheat, the heat pipe fin stack being joined to the complex heat pipes andconfigured to transfer the second portion of the extracted heat receivedfrom the complex heat pipes to air surrounding the stack.

In an example of the aspect, the complex heat pipes extend from thechamber through the fins and the heat pipe fin stack. In an additionalexample of the aspect, the fins are bonded to the baseplate in aplurality of groups, and the groups are separated from each other by thecomplex heat pipes. In a further example of the aspect, the complex heatpipes extend from the chamber through two of the fin groups and the heatpipe fin stack. In yet another example of the aspect, the chamber ismounted horizontally in the baseplate. In another example of the aspect,the chamber is embedded in the baseplate. In a still further example ofthe aspect, the chamber is positioned in a baseplate channel comprisingwalls defining the baseplate channel, the chamber being secured to thewalls.

Other features and aspects may be apparent from the following detaileddescription, the drawings and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an example of a hybrid heatpipe assembly.

FIG. 2 is front view illustrating an example of the hybrid heat pipeassembly shown in FIG. 1.

FIG. 3 is a side cross-sectional view taken along lines 3-3 of FIG. 2illustrating an example of the hybrid heat pipe assembly shown in FIG.1.

FIG. 4 is a close-up view of area 4 of FIG. 3 illustrating an example ofan interface of a baseplate and a complex heat pipe of the hybrid heatpipe assembly shown in FIG. 1.

FIG. 5 is a perspective view illustrating an example of a complex heatpipe of the hybrid heat pipe assembly shown in FIG. 1.

FIG. 6 is a perspective view illustrating an example of the hybrid heatpipe assembly shown in FIG. 1 with devices in contact therewith.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals will be understood torefer to the same elements, features and structures. The relative sizeand depiction of these elements may be exaggerated for clarity,illustration and convenience.

DETAILED DESCRIPTION

Examples incorporating one or more embodiments are described andillustrated in the drawings. These illustrated examples are not intendedto be limiting. For example, one or more aspects of an embodiment may beutilized in other embodiments and even other types of devices.

FIGS. 1-6 illustrate an example hybrid heat pipe assembly in surfacecontact with a plurality of devices 4. While the devices 4 illustratedin FIG. 6 bear a common resemblance with electronic modules, embodimentsdescribed herein are not limited thereto. In fact, one having ordinaryskill in the art may use the hybrid heat pipe assembly 2 to cool anyapplicable heat-generating device having the ability to be in contactwith the hybrid heat pipe assembly 2.

While the devices 4 illustrated in FIG. 6 are mounted to the hybrid heatpipe assembly 2 using fasteners 6, embodiments described herein are notlimited thereto. For example, the devices 4 may merely be in contactwith the hybrid heat pipe assembly 2 without being fixed or mountedthereto. In addition, the devices 4 contacting the hybrid heat pipeassembly 2 may be related or unrelated to each other. Moreover, thedevices 4 may be in contact with or isolated from each other. Whateverthe case, the devices 4 to be cooled by the hybrid heat pipe assembly 2are positioned with respect to the hybrid heat pipe assembly in such away as to maximize surface contact with the hybrid heat pipe assembly 2,thereby serving to increase an amount of heat extracted from the devices4 by the hybrid heat pipe assembly 2.

The illustrated hybrid heat pipe assembly 2 may combine various aspectsand elements of a bonded fin heat sink and a heat pipe apparatus.However, the hybrid heat pipe assembly 2 is not limited thereto and canbe further supplemented by other heat transfer means known by those ofordinary skill in the art.

The example hybrid heat pipe assembly 2 described and illustrated hereinincludes a baseplate 8 in contact with the devices 4, baseplate fins 10bonded to the baseplate 8, a complex heat pipe 12 extending from thebaseplate 8 and having an end positioned within the baseplate 8, and aheat pipe fin stack 14 joined to the complex heat pipe 12.

The baseplate 8 is configured to extract heat from the devices 4 incontact with the baseplate 8. As was previously noted with respect tothe hybrid heat pipe assembly 2, while the devices 4 illustrated in FIG.6 are mounted to the baseplate 8 using fasteners 6, embodimentsdescribed herein are not limited thereto. For example, the devices 4 maybe in contact with the baseplate 8 without being fixed or mountedthereto. In addition, the devices 4 may be related or unrelated to eachother or other items contacting the baseplate 8.

The baseplate 8 may have a shape consistent with that of a rectangularblock. However, embodiments disclosed herein are not limited thereto asthe baseplate 8 can have any shape or structure that is effective incooling devices in contact therewith. Further, while the baseplate 8 isillustrated in the example herein as being flat or planar, embodimentsdescribed here are not limited thereto, as the baseplate 8 may be curvedor otherwise to maximize surface contact with the devices 4 and extractheat from the devices 4 as efficiently as possible. Thus, the shape anddesign of the baseplate 8 may be adjusted for effective extraction ofheat from whatever device might be in surface contact therewith.

The baseplate 8 may be mounted on a corresponding structure such that anedge line 20 of the baseplate 8 is parallel with gravity. However,embodiments disclosed herein are not limited thereto, as the baseplate 8can be mounted in any plane particularly suited for cooling the devices4 in contact therewith, as long as requirements for cooling theheat-generating devices 4 are met and acceptable support is provided forthe baseplate 8.

The heat extracted from the devices 4 by the baseplate 8 may betransferred therefrom to the baseplate fins 10 bonded to the baseplate8. The heat received by the baseplate fins 10 may be directlytransferred to the air surrounding the baseplate fins 10.

The baseplate fins 10 may be mounted directly on the baseplate 8 or on afin plate 30 that is subsequently mounted on the baseplate 8. If mounteddirectly on the baseplate 8, each of the baseplate fins 10 may include aflange (not shown) via which the baseplate fin 10 is fastened to thebaseplate 8. The flange may extend from an edge of a body 32 of thebaseplate fin 10 in a substantially perpendicular manner that isadditionally substantially parallel with the sides 16, 18 of thebaseplate 8. The baseplate fins 10 may be bonded to the baseplate 8 in aplurality of groups. In addition, the baseplate fins 10 may be mountedto an opposite side 16 of the baseplate 8 from a side 18 of thebaseplate 8 in contact with the devices 4.

In some cases, when cooling requirements for the devices 4 are great,the heat generated by the devices 4 may be too substantial to beeffectively dissipated solely by the baseplate fins 10. When thisoccurs, the excess heat may be dissipated from the baseplate 8 throughthe complex heat pipe 12. The complex heat pipe 12 may transfer thereceived excess heat from the baseplate 8 to the heat pipe fin stack 14for subsequent dissipation to air surrounding the heat pipe fin stack14.

As is the case with the baseplate fins 10, the complex heat pipe 12 mayalso be positioned on the opposite side 16 of the baseplate 8 from theside 18 of the baseplate 8 in contact with the devices 4. In addition,the complex heat pipe 12 may be mounted on the complex heat pipe side ofthe baseplate 8 in a location that corresponds with a location of thedevices 4 positioned on the opposite side 18 of the baseplate 8. Whenthe complex heat pipe 12 is mounted on the baseplate 8 in such alocation, the heat extraction from the devices 4 may be more efficient.

The complex heat pipe 12 may be similar in design to a clarinet heatpipe or a tube that has been fabricated to seal a working fluid undervacuum pressure. Several complex heat pipes 12 may be mounted in thebaseplate 8 to extend therefrom. Ends of the complex heat pipes 12 mayalso be embedded in the baseplate 8.

As such, a complex heat pipe 12 may separate one group of the baseplatefins 10 from another group of the baseplate fins 10. The complex heatpipe 12 may extend from the baseplate 8 and through the baseplate fins10 and the heat pipe fin stack 14. The baseplate fins 10 may be mountedto and arranged on the baseplate 8 in a plurality of separated groups.In such cases, the groups of the baseplate fins 10 may be separated fromeach other by a complex heat pipe 12 extending from the baseplate 8,between the groups of the baseplate fins 10, and through the heat pipefin stack 14. For example, two groups of baseplate fins 10 may beseparated by a complex heat pipe 12 mounted to the baseplate 8 in anarea between the two groups of the baseplate fins 10. The complex heatpipe 12 may extend between and past the baseplate fins 10 and into theheat pipe fin stack 14. The heat pipe fin stack 14 may be separated fromthe baseplate 8 by the baseplate fins 10.

Further, a complex heat pipe apparatus 22 may include a plurality of thecomplex heat pipes 12 secured within a closed chamber 24 that ispositioned within the baseplate 8. The complex heat pipes 12 may besecured within respective recesses in the closed chamber 24 by brazingthe heat pipes 12 to respective walls that define the recesses. Thechamber 24 may be embedded in a baseplate channel 26 formed within thebaseplate 8 such that chamber 24 can fit therein. For example, thechamber 24 may be welded to walls that define the baseplate channel 26.The closed chamber 24 may act as a fluid reservoir within the baseplate8 to expedite the transfer of heat from the baseplate 8 using atwo-phase flow cycle created within the complex heat pipes 12.

Moreover, the closed chamber 24 may be mounted at a location in thebaseplate 8 that enhances or maximizes heat extraction from the devices4. For example, the chamber 24 may be placed within a baseplate channel26 at a location on the side 18 at which the devices 4 make surfacecontact with the baseplate 8. The baseplate channel 26 location on theside 16 may be essentially opposite a location on the side 18 at whichthe devices 4 are in surface contact therewith.

Further, the chamber 24 and the channel 26 may be correspondinglyoriented to maximize exposure to devices 4 in surface contact with thebaseplate 8 in order to enhance or maximize extraction of heattherefrom. For example, while both the chamber 24 and the channel 26 areillustrated herein as being straight, embodiments disclosed herein arenot limited thereto, as the channel 24 can be correspondingly curved toa curved channel 26 and of the baseplate 8 in order to maximize heatextraction from a correspondingly positioned and/or shaped group ofdevices 4 making surface contact with the baseplate 8.

The heat pipe fin stack 14 may include a heat pipe protective fin 28 toprovide protection for a complex heat pipe 12 extending therethrough.The heat pipe protective fin 28 may be positioned on an opposite side ofthe heat pipe fin stack 14 from the baseplate fins 10 and adjacent toone end 36 of the complex heat pipe 12. The pipe end 36 may extendthrough the heat pipe protective fin 28, such that the pipe end 36 isseparated from a remainder of the complex heat pipe 12 by the heat pipeprotective fin 28. Further, an end cap 34 may be positioned on the pipeend 36 of the complex heat pipe 12 to provide additional protection tothe complex heat pipe 12.

In the examples described herein, the complex heat pipe 12 is positionedto absorb excess heat from the baseplate 8 when cooling requirements arehigh enough that the baseplate fins 10 are unable to effectively coolthe devices 4 contacting the baseplate 8. As a result, melting of adevices 4 due to insufficient cooling may be inhibited.

A number of examples have been described above. Nevertheless, it will beunderstood that various modifications may be made. For example, suitableresults may be achieved if the described elements are combined in adifferent manner and/or replaced or supplemented by other elements ortheir equivalents. Accordingly, other implementations are within thescope of the following claims.

Having described the invention, the following is claimed:
 1. A hybridheat pipe assembly comprising: a baseplate dimensioned to be placed insurface contact with a device, the baseplate being configured to extractheat from the device; a plurality of fins bonded to the baseplate, thefins being configured to transfer a first portion of the extracted heatfrom the baseplate to air surrounding the fins; a complex heat pipeextending from the baseplate and having an end positioned within thebaseplate, the complex heat pipe being configured to receive andtransfer a second portion of the extracted heat transferred from thebaseplate; and a heat pipe fin stack to which the complex heat pipe isconfigured to transfer the second portion of heat, the heat pipe finstack being joined to the complex heat pipe and configured to transferthe second portion of the extracted heat received from the complex heatpipe to air surrounding the stack.
 2. The assembly of claim 1, whereinthe complex heat pipe extends from the baseplate and through the finsand the heat pipe fin stack.
 3. The assembly of claim 1, wherein thefins are bonded to the baseplate in a plurality of groups, and whereinthe groups are separated from each other by the complex heat pipe. 4.The assembly of claim 3, wherein the complex heat pipe extends from thebaseplate and through two of the fin groups and the heat pipe fin stack.5. The assembly of claim 1, wherein the heat pipe fin stack is separatedfrom the baseplate by the fins.
 6. The assembly of claim 1, wherein thefins are bonded to the baseplate in a plurality of groups, wherein thecomplex heat pipe is one of a plurality of complex heat pipes, andwherein each of the complex heat pipes separates one of the fin groupsfrom another one of the fin groups.
 7. The assembly of claim 6, whereineach of the complex heat pipes extends through the heat pipe fin stack.8. The assembly of claim 1, wherein the heat pipe fin stack comprises aheat pipe protective fin into which the complex heat pipe extends, andwherein the heat pipe protective fin is positioned on an opposite sideof the heat pipe fin stack from the fins.
 9. The assembly of claim 8,wherein the heat pipe protective fin is positioned adjacent to one endof the complex heat pipe.
 10. The assembly of claim 9, wherein anotherend of the complex heat pipe is embedded in the baseplate.
 11. Theassembly of claim 1, wherein the fins are mounted to an opposite side ofthe plate from a side of the baseplate in contact with the device. 12.The assembly of claim 1, wherein the complex heat pipe is embedded inthe baseplate.
 13. The assembly of claim 12, wherein the complex heatpipe extends at an angle from the baseplate to an end of the complexheat pipe.
 14. A hybrid heat pipe assembly comprising: a baseplatedimensioned to be placed in surface contact with a device, the baseplatebeing configured to extract heat from the device; a plurality of finsbonded to the baseplate, the fins being configured to transfer a firstportion of the extracted heat from the baseplate to air surrounding thefins; a complex heat pipe apparatus positioned within the baseplate, theapparatus comprising a chamber positioned within the baseplate and aplurality of complex heat pipes secured within the chamber, the complexheat pipes extending from the baseplate and having ends positionedwithin the baseplate, the chamber being configured to receive a secondportion of the extracted heat transferred from the baseplate andtransfer the second heat portion to the complex heat pipes, the complexheat pipes being configured to receive and transfer the second heatportion from the chamber; and a heat pipe fin stack to which the complexheat pipes are configured to transfer the second portion of heat, theheat pipe fin stack being joined to the complex heat pipes andconfigured to transfer the second portion of the extracted heat receivedfrom the complex heat pipes to air surrounding the stack.
 15. Theassembly of claim 14, wherein the complex heat pipes extend from thechamber through the fins and the heat pipe fin stack.
 16. The assemblyof claim 14, wherein the fins are bonded to the baseplate in a pluralityof groups, and wherein the groups are separated from each other by thecomplex heat pipes.
 17. The assembly of claim 16, wherein the complexheat pipes extend from the chamber through two of the fin groups and theheat pipe fin stack.
 18. The assembly of claim 14, wherein the chamberis mounted horizontally in the baseplate.
 19. The assembly of claim 14,wherein the chamber is embedded in the baseplate.
 20. The assembly ofclaim 14, wherein the chamber is positioned in a baseplate channelcomprising walls defining the baseplate channel, the chamber beingsecured to the walls.